Pain is a central concern for the practice discipline of nursing, and has particular importance for the advanced practice specialty of nurse anesthesia. Given the neuro-chemical and anatomical pathways linking the brain and immune system, postoperative pain following tumor removal may suppress immune mechanisms central to immunosurveillance. Immunosurveillance may be critical during the postoperative period because tumor manipulation is postulated to lead to micro-metastatic tumor dissemination. Animal models implicate pain in postoperative immunosuppression, yet the role of pain perception in perioperative immunosuppression in humans is less clear. Thus, the purpose of this study is to understand the influence of pain perception on immune function {NK cell number and activity) in men during the perioperative prostatectomy surgical experience. Because of the potential effect of psychological stress on pain perception and immune function in patients undergoing cancer surgery, this study will examine the following psychological modulating factors: perceived stress, anxiety, mood, sense of coherence, and adaptation to cancer. Plasma beta endorphins, the hormones secreted in response to pain, will also be measured. Men (45-70yrs) scheduled for prostatectomy and age matched men without cancer will be enrolled. Pain perception, plasma endorphins, psychological factors, and immune function will be measured at baseline (pre-surgical visit); 24 and 72 hrs post-surgery; and at the 4-6 week postoperative visit. Correlations among variables and differences based on level of pain and level of immune function will be determined. This biobehavioral approach is consistent with nursing practice and will provide the first description of pain perception, stress, and immunity in men undergoing prostatectomy.